Electromechanical selector.



E. G. GODFREB.

ELECTROMECHANIGAL SELECTOR.

APPLIGATION FILED MAY 7,1910.

997,990, Patented July 18,1911.

4 SHEETSSHEET 1.

E. G. GODFREE; 'ELEGTROMEGHANIOAL SELECTOR.

AP PLIGATION YILBB MAY 7. 1910.

Patented July 13,1911.

4 SHEETS-SHEET 2. v

' ELEGTRDMECHANIGAL SELECTOR.

APPLICATION FILED MAY 7,1910.

Patented July 18 4 SHEETS-SHBBT 3.

9.. G'. GODFREE. ELEGTROMEGHANIGAL SELECTOR.

APPLICATION FILED MAY 7 1910 Patented July 18,1911

4 sw ms-mum 4.

ERN ST GRAHAMIGODF'REE, or HAMrToN, NEAR MELBOURNE, vmwof a-amtmm.

understood it will bedes'cribed with referto the accompanying drawings,-in M i 1 and lifts said pawl out of engagement-w th the tooth orprojection 13. When the-lever .1 is released the spring 2 tends to-return it'' UNITED STATES PATENT ELncrnoMiio A oAL sEL'Ec'roR.

To all whom itmay concern:

Be it known that I, ERNEST GRAHAM Gon- FREE, a citizen of the,Commonwealth of Australia, residingat Service street, Hampton, nearMelbourne, in the State of Victoria and said Commonwealth, clerk, haveinvented a new and useful Electromechani-- cal Selector, OfWlliCllrtllBfollowing is a,

specification. This nvention has been devised in-order to provide asimple and reliable electromechanicalselector for use in connectionwith' electro-signaling'or for party line telephone interlocked with thesuch a manner as to tion while the line is engaged.

The transmitter consists, preferably, of

motlve mechanism soa clock workor other constructed that when releaseditoperates suitable, electrical contacts send electrical impulses throughthe circuit. The number of impulses sent depends on the insertion of asuitable plug or' stop in any one of'a number of holes provided for thepurpose around the. circumference of: a dial.

The receiving part of theinstrument com- I prises an electro-magnet' andarmature arranged to operate .certainelectrical contact making devices,a ratchet wheel having one shallow tooth, a rubbing spring contact, adetent retaining pawl and "a swingingor fly contact, a local circuitconsisting of the contact on 'the pawl of the armature, the

spring contact, a'batteryand a bell.

In order that the invention may be readily ence which: p

Figure 1' is a front elevation of the apparatus. Fig. 2 is a frontelevation of the apparatus with the cover, dials and partof theframework removed showing 'L-he' mecha- 7 Application filed May 7,1910.Serial No. 559,935. I

thus giving the same faciliwould be' obtained with the use of a separateline wire. The transmitting part of the instrument is mechanicallyreceiving instrument in prevent any interrup-' position, is adaptedwhich in turn.

Specification of Letters Patent. P t t nism. Fig. 3 isa side elevationof the ap} paratus with part ofthe casing and a cer i tain spring (2)removed for sake erase ness. Figs. 4 and .5 are front elevations-ofcertain important details of the selec-tor hereinafter described showingthe parts in different positions. Figs. 6 and 7 are views llustratingcertain locking mechanismhere inafter described. Fig.':8illustra tesdetails .of certain other lockingmechanism. Figs.

9 and 10 are views showing certain contact apparatushereinafter'described. Fig. 1"1.is a diagrammatic view illustrating thewiring of part of the apparatus. Fig. 12 is 21 diagrammatic viewillustrating a system of wiring for this, invention. Y

Like reference 'numerals'indicate the same partsthroughout thedrawings." The lever 1 which is illustrated through,- out the drawingsin its raised .or normal wardly against the tension of the .spring2shown in Fig. 2. A pawl .3 mounted on the lever 1, engages with aratchet wheel 4, when said. lever is released. This movement operatesthe, gear wheel .5 which gearing to be pressed i'downwith a smaller gearwheel 6. revolves the wheel'7i This latter has a number of projections 8formed on its circumference con responding to the number of'st-ationson; the

line. another set of gear wheels 9 whichintu rnf drive a fan 10 actingas a governor or controller. I

' The wheel 7 is automatically "lockedj'i in its normal position bymeans .of'pawls 11 and 12m'ounted on the supporting fr'ame oftheapparatus and arrangedlto engage one on each side of a toothorprojection'13 secured to the shaft which carries the wheel 7 A stud orprojecting pin 15sec Fig; is

formed or pr'ovided on the pawlfll2. The

' .95 at its lower endJWVhen the leverlt isydef pressed the arms 16 and17 rise anda lateral; projection 173E off the arm 17 engages with lever1 is formed} with two arms "16 and 17 the stud or projecting pin Loonthe"pawl-l2" p e wheel. 5 :I als ohdrives,

gearing which causes the wheel 1 7 one full revolution, or part of arevolution as hereinafter explained.

A small wheel or roller 18 on the upper end of a contact spring 19 bearsagainst the periphery of the wheel 7, and during the movement of samemakes and breaks cert ain electric circuits through other contactsprings 20, 21, and 22 illustrated in Fig. 2. An-electro-magnet 23 isnormally in electrical communication with the contact 20 ready toreceive any impulse sent along the line but as the wheel 7 revolves itsprojections 8 force back the contact spring 19 and cause it to makecontact with the springs 21 and 22 thereby putting the line battery incircuit also the telephone transmitter and receiver at the'sendingstation. An impulse is thus sent through the electro-magnet 23 when eachprojection 8 on the Wheel 7 forces back said contact spring 19.

An armature 24 is attached to a pivotally mounted arm 25 which carries apawl'26 adapted to engage with a selecting ratchet wheel 27. The teethon said ratchet wheel correspond with the stations on the line plus twoextra teeth one corresponding with the locked and one with the zeroposition of the instrument. An arm 25 also projects from the lever 25and engages with the teeth of the ratchet wheel 27 in such a way as toprevent any over-running of said wheel--,,while a roller 25 upon aspring 25 bears against the teeth of said wheel and holds it in positionuntil it is moved on another tooth by the forward movement of the pawl26. One tooth 28 on the ratchet wheel is "formed shallower than theothers, that is, about half as deep or less than the other teeth, asillustrated in Figs. 2, 4 and 5.

The position of'the shallow tooth 28 of the ratchet wheel 27 isdifferent in each instrument. For instance the position of the tooth innumber one instrument would be two movements from the normal position,that is when the indicator hand is at zero.

' At number two stat-ion the shallow tooth would be three movements andso on, the shallow tooth in each consecutive instrument beingonemovement behind that at the preceding station.

A projecting arm or cam 29 is attached to the ratchet wheel 27 and inits normal position bears against a roller 30 on the upper end of apivotally mounted locking arm or lever 31 as illustrated in Figs. 1, 2,and 4. Thelocking arm or lever 31, is in halves pivotally connectedtogether by a knuckle joint. The lowerend 32 of the bottom half of thelocking lever is adapted to engage the end of the arm 16 of'the lever 1,as illustrated in Fig. 8, immediately the first impulse is sent throughthe electromagnet 23 and the ratchet wheel 27 is moved around asindicated-in Fig. 8. A spring 33 allows a certain amount of independentmovement be tween the two halves of the lever and thus insures that noundue pressure will be exerted on the projecting arm 29 even if thelever 1 was being pressed down by the operator, at the time an impulsewas going through his instrument-s: sist-s in returning said lever toits locking position, and a set screw 35 limits the movement of same.

The pivotally mounted arm 25 is formed with a laterally projecting armor extension 25 the end of which passes through the bifurcated end of acheck piece or rest 36 and contacts with a flying spring contact 37 eachtime the armature 24 is attracted by its electro-magnet 23. The contact37 is carried at the lower end of a very light spring 37, the upper endof which is supported by a bracket 37 secured to a block 37 ofinsulating material. The check piece or rest 36 prevents the flyingspring contact from making contact with the arm 25 when the instrumentis at normal that is whenthe arm 25 is drawn back. I

The pawl 26 contacts with a hit and miss contact 38 once each revolutionof the ratchet wheel 27 that is, when the pawl 26 is raised higher thanusual by means of the shallow tooth 28 as illustrated in Fig. 5. Aspring 39 tends to return the arm 25 to its normal position and a setscrew 40 limits the movement of' said arm.

A locking device is provided so that when the instrument is not in usethe lever 1 is locked and thus prevented from moving downwardly. Thisdevice consists of an upwardly projecting arm 41 and a horizontal arm 42pivotally mounted in a bracket or support 43 on the base of theinstrumentunder or near the lever arm 1; A spring 44' connects the twoarms 41, 42 and yet allows a certain amount of give to the arm 41. Acontact spring 45 tends to make contact at 46 as illustrated in Figs. 6and 7.

To look the lever 1 a plug 47 is inserted through an aperture in theplug holder 48 and forces the arm 42 upwardly. 'This arm bearing on thespring 44 causes the arm 41 to move back into position under aprojection or stop 49 on the lever 1, at the same time breaking contactat 46. This is the normal position of the plug 47 when the instrument isnot in use. The object of the spring 44 above referred to is to allowthe arm 41 to give slightly if pressed against the lever 1 by insertingthe plug 47 in the holder 48 before the stop 49 has oeen raised clear.

As illustrated in Fig. 1 the instrument has an upper and a lower dial 50and 51 respectively. The top dial 50 in this instance is numbered from 1to 12 and has in addition a zero or normal condition indicator andanother indicator for a locking movement of the instrument. An indicatorhand 52 A spring 34 aswhether the instrument is either at zero or:

controlled by the ratchet wheel 27 indicates locked, or connected withany particular stationQ The lower dial 51 has a number of holes formedin it, corresponding to the number of stations on the line. In theinstance illustrated the drawings there are supposed to be twelvestations. This .dial is placed directly in front of the' contact makingwheel 7. 4

The normal condition of the instrument is with the receiver on the hook53, the indicator pointing at zero, and the plug 17 in the support 18locking the lever 1 as previously described. Figs. 2and4=illustrate theratchet wheel 27 as it would be set at number'four station when theindicator hand is pointing at zero. One of theinstrumen'ts abovedescribed will be provided at each station and in their normal conditionwill all be at zero. Their mode of operation is as follows.

Say for instance the operator in number one station desires to ring upnumber four tion along the line. He removeshis plug 47 from the plugholder 48, thus unlocking the lever 1, inserts said plug in hole numberat in the lower dial 51, depresses said lever 1 to its full extent andthen releases same. When the lever 1 is depressed the projection l7 onthe arm 17 in its upward movement bears against. an ebonite' or otherinsulator 51 on the contact spring55 which normally is in contact withanother spring contact-56 as illustrated in Figs. 2' and 12 of thedrawings; The insulator .54, is situated in the path of travel of thearm 17 which thus forces the contact spring down until contact is madewith the lower contact spring 57. This closes a circuit when theinstruments are properly connected and sends an impulse through theelectro-magnet causing the pawl 26 to operate the ratchet wheel 27 andturn it the extent of one tooth. The circuit so closed may be traced asfollows on the diagrammatic view Fig. 12. From main line wire a throu hcontact 18,

b H, contact 20 wire 0 to spring contact on, to

contact 57, through wire (Z and battery 7 to' wire e,'to magnet 23 andto main line wire .7). This movement takesplace right alongthe line andreleases the locking levers 31 simultaneously in all the instrumentsthus allowing the springs, 3 1 to pull the lower ends of said leversinto engagement with the arms 16 of the operating levers l and therebylocking said levers in .all the stations. This prevents any otherinst'ru} ment exceptthe first from being operated until the operator innumber one station (that is the selecting station) and the oper-..

ator in the selected station -(in this instance number four) havefinished using their.in-' struments either for conversation or signal:

ing. and hav returned same. to normal. When the lever 1 1s released andreturns to sta- its normal position the projecting "end, 17 of the arm17 of ebonite or'other insulatorfitflso as not to make another contacton-the. spring contact 57. The wheel 7 continues to revolve until a stopor projection 7 upon comes against the plug 17 projecting hole Beforethis happens four, more imtacts made by the rollerl-8 being forced outby the projections-8 on theperiphery of the wheel 7 as it is revolved.)'are sent through the electro-magnet .23. This circuit may be traced asfollows on Fig. 12. From line wire a to contactarm 18, thence-to contact'21, thence through local battery and This means that five impulses havebeen sent therefore been moved on five teeth. This brings the shallowtooth 28in number four station into position under the-pawl 26 asillustrated in Fig. 5. The pawl 26 in that station is therebyraised-high enough forthe projection or contact 'piece'a26? to contactwith spring contact 38, and vthe'fly con- 7 tact 37 coming to rest .onthe armature arm that when the pawl and the swinging or at the same timefly time to swing tic'n against the arm 25 tions in the present instanceonly occur: in

contact 87 must have had from local battery 9 by wire-Z to contacts orswitch 53, thence to contact 38 to arma ture contact 25 by wayof'contact2b on pawl 26,- thence to flying contact 37 to'bell and bywire h to battery 9. The hit and miss to return to their contacting=..positio1is before I u, l I u I tion with each othem-and the bellis ringing said lever passes under the through number four pulses(corresponding to the numberof con wire e tomagnet-23 and to main linewire 6..

through said magnet, since the-first move-.. mentof the lever 1.Thelratchet: wheel has and is raisedby the tooth 28 in any particularstation .The' pawl 26 must be raised by the shallow tooth and contactbemade between the contact 26" on the pawl 26 hit or miss" contact 38,

back into its contacting posi-' Thesetwo condi'a 110 number four stationbecause-that is the sta-- tion in which the shallow'toot-h 28 will be inposition to hold up the contact 26 on the pawl 26. The local bellcircuit. in the called station may be traced in Fig. 12 as follows 59which are bridged by the telephone hook 1 contact-in the other stationsbeing only mo mental-y the fly contacts 37 do not-have time.

the armature 24'and lever.25 have been '(ll'ilWIl back and the hitandmiss contact has been thereby broken. Numbers one and four machines areriowindirect co-mmunic'a- 1 i in number four. station and will continueto 25 the local bell circuit is'closedrand'the ring until the receiveris takenoff its hook,

58. The inner arm 53 of the hook 53 will then be pulled down by thespring 58 from under two rubbing springs 59 of the bell circuit and willbridge the twosprings 60 of the speaking circuit, or otherwise bring thespeaking circuit into operation.

A pin 61 provided on the inner arm 53 bears againsta pivotally mountedlever arm 62 and forces it outwardly against the tension of a spring 63,when the receiver is taken oil the hook 53. The spring 63 returns thearm 62 to normal when the receiver is replaced on the hook 45. Theseparts are illustrated in Figs. 9 and 10 as viewed from the rear with theback board of the instrument removed. An upwardly pro jecting arm 64mounted on the spindle of the locking lever 31 carries a contact spring65 arranged to contact with a terminal 66 when the receiver is taken offthe hook and the lever arm 62 is withdrawn by the pin 61 on the arm 53*.The spring 65 thus makes contact with the terminal 66 and. completes thespeaking circuit when the two lower rubbing springs 60 are bridged bythe arm 53. The contact stops 62 on the arms 62 hold the contact springs65 on all the instruments (except at the station selecting and at thestation selected) out of contact with the terminals 66. As the contactspring 65 is carried by the spindle of the locking lever 31, it will bereplaced upon .the contact 66, when the apparatus is restored to normalcondition and the locking lever is restored to its normal position shownin Fig. 10. Numbers one and four stations are now in directcommunication with each other. The telephone circuit may be traced asfollows in Fig. 12. From ground through the telephone instrumentindicated at 0, by wire 7) to the wire 9, armature contact 25 contact37, wires r and i to contacts 45, 46, wire it to terminal 66, contact65, wire 8 to line wire I). The local battery circuit for the telephoneinstrumentis closed by hook or switch 53 bridging contacts 60, 60 andmay be traced from one of said contacts by wire m to wire it to batteryg, thence by wire Z back to the other contact 60. At the close ofconversation or signaling as the case may be the receiver is hung on thehook, 53, thus breaking the speaking circuit and making the bellcircuit. This circuitmay be traced on Fig. 11 from local battery 9through wire Z to contacts 59, 59 which are bridged by the 11001653, bywire 8 to wire 5, thence by contacts 65, 66 to wire 70, through contacts46, 45 to wire 2', to bell, and by wire it to battery. The bell willcontinue to ring at the selecting station until the plug 47 is removedtrom the hole in the dial and is inserted in the plug support 48, thusbreaking the contact between the spring 45 and the contact point 46, asillustrated in Figs. 6 and 7 and also in the wiring diagrams Figs. 11and 12.

In the diagrammatic view, Fig. 12, a represents part of the main linecircuit, leading into one of the stations, and 5 represents the mainline wire leading out from the same. The line wire a is connected to thearm carrying the roller 18 which is normally in engagement with thecontact 20. Gontact 20 is connected by a wire 0 with the spring arm 55carrying the insulator 54; a wire d connects the contact 57 with thecontact 21 and a wire 6 connects contact 56 with the magnet 23 of thelocal station, which is also connected to the leading out wire 5. Alocal battery f is connected in a shunt between the wires (Z and e. Awire it connects the hell with local battery 9, wire 2' connects thebell with the spring 45, and contact 46 is connected by wire is with theterminal 66 hereinafter referred to. A wire Z connects the bat ery 9with one of the pairs of contacts 59 and 60, for throwing the batteryinto either the bell or telephone circuits ac cording to the position ofthe telephone hook or lever 53. m is a wire leading from the othercontact 60 to wire it and n is a wire from the contact 62, to wire 9,thence to contact 25 0 represents the telephone connected to wiregrounded at one end and connected at the other to the wire {I throughthe secondary or speaking circuit. The wire (1 connects contact 22 withcontact 25 on the armature lever, a wire 1 connects the flying contact3? with the bell circuit (as the wire 2') and a wire 8 connects thecontact 38 with the line wire I) and with the arm 64, and a continuations from wire .9 extends to one of the contacts 59.

Fig. 11 represents diagrammatically a portion of the apparatus on alarger scale, illustrating the circuits connected therewith.

\Vhen the plug or stop of the transmitting instrument is withdrawn thelever 1 and the mechanism return to their normal condition with theindicator hand pointing to Zero and a sufficient number of impulses aresent along the line to return all the 1 instruments to their normalpositions.

It will be seen from the foregoing that the transmitting and receivinginstruments at each place are mechanically interlocked so that it isimpossible for an operator in another station on the line to use histransmitting instrument while the line is engaged.

It will be understood by persons conversant with the art to which thisinvention relates that the electro-mechanical selector above describedcan be modified in various ways without departing from the essentialfeatures of the invention. For example reciprocating movements may beadapted in lieu of rotating ones and other forms oI electrical contactsmay be adapted in place of those shown and described in the drawings andspecifications.

Having now fully described and ascertained my said inyention and themanner in which it is to' be performed, I declare that what I claimis 1. In an electro-mecha'nical selector, the combination with impulsetransmitting mechanism, of a manually operated device, operativelyconnected therewith, a locking device for preventing the operationof'said manually operated device, and comprising two pivoted arms, oneof which is adapted to engage said manually operated device, and ayielding connection between said arms,v yielding means for holding thelocking device in its normal position, a stepby-step selecting device,electrically connectcd with the impulse transmitting mechanism and adevice carried by said selecting device, for engaging the other of saidarms of the locking device, when the selecting device is in normalposition, and holding the locking device out of operative position.

In an electro-mechanical selector, the combination with impulsetransmitting mechanism, of a manually-operated device operativelyconnected therewith, a locking device for preventing the operation ofsaid manually operated device when in normal position, a step-by-stepselecting device, electrically connected with the impulse transmittingmechanism, and a device carried by the said selecting device forengaging said locking device,when theselecting device is in normalposition, and holding it out of engagement with the manually operateddevice, an auxiliary contact device for making a circuit through thestep-by-step selecting mechanism, and a part connected with saidmanually operated device for actuatingsaid contact device, operatingsaid selecting device and releasing said locking device, before theimpulse transmitting mechanism is actuated;

3; In an electro-mechanical selector the combination with impulsetransmitting mechanism, actuating devices for imparting a predeterminedmovement to said impulse transmitter, a manually operated device.movable freely in'one direction, a pawl and ratchet mechanism connectingsaid manually operated device with the impulse transmitting mechanismand a yielding device for restoring said manually operated device tonormal position, and actuating the impulse transmitting mechanism; astep-bystep selecting device, including a selecting wheel, adapted to begiven. a complete revolution by the impulse transmitting mechanism, alocking device for holding the manually operated device from movement.and

a device carried by said selecting wheel for engaging said lockingdevice wheii' said movement of said manually operateddevice,

and a removable and adjustable plug for arresting the impulsetransmitting mechanism.

it. In an electro-mechanical selector, the combination with impulsetransmitting mechanism, including a rotary circuit making andbreaking'disk, and contact devices cotiperating therewith, actuatingdevices for imparting a complete revolution to said disk at eachoperation, and an auxiliary contact device adjacent to saiddisk, astep-by-step selecting device, in circuit with said disk controlledcontacts and said auxiliary contact, and including a selecting Wheeladapted to be given a complete revolution by the operation of saidauxiliary contact device" and said disk controlled contact devices, at

each operation of the devic'e,-a switch ina call circuit, a lockingdevice'for the man ually operated dev1ce,;a spring-for hol'dlng saidlocking device in operative position, a.

device carried by said selectingwheel Ltor holding said locking devicenormally out of. operation when the said wheel is in normal position,and a device carried by said Wheel for operating said switch, and apart-'con-' nected With said manually operated-device.

for actuating said auxiliaryicontact device of the impulsetransmittingmeclianism to release the said locking device during thefree movement of the manually operated. device. before said actuatingdevice, is brought into operation, and'a removable and adjustable. plugfor arrestingisaid disk.

5. In an electro-mechanical selector, the combination with impulsetransmitting mechanism, comprising among its members a rotary diskadapted to transmitanumber of impulses equal to the number of stationson the line, said disk being provided with a locking projection, lockingpawls engaging said projection on opposite sides thereof and holdingsaid disk in normal position, actuat-.- ing devices for imparting acomplete revolution to said disk, a manually operated device. forputting said actuating devices into openation, a part carried by saidmanually 'operated device for engaging one of saidpawls to release thedisk, and permit its, operation by said actuating devices, and aremovableand adjustable plug for arresting saiddisk in differentpositions. V

-6. In an electro-mechanical selector, the. combination with impulsetransmitting. mechanism, actuating devices therefor .a

voperated removable plug for holding said second locking device inoperative position.

7. In. an electro-mechanical selector, the combination with the impulsetransmitting mechanism including a rotary disk and con- I tact deviceoperated thereby, gearing for imparting a complete revolution to saiddisk, 9. hand lever movable freely in one direction pawl and ratchetmechanism connecting said lever with said gearing, an actuating springconnected with said lever, a lock for holding said disk in normalposition, a locking device for holding said lever against movement, anelectric selecting device, a part carried thereby for engaging saidlever look when the selecting device is in normal position and holdingit in inoperative position, a second lock for said hand lever, normallyheld out of engagement therewith, a manually operated plug for forcingsaid second look into engagement with said lever, a part carried by saidhand lever for disengaging the lock for said disk, an auxiliary contactdevice electrically connected with the selecting device, and a partcarried by said lever for operating said contact device to move theselecting device a step and disengage the lock engaging part from thelever locking device. 7

8. In ,an electro-mechanical selector, the combination with a manuallyoperated device for actuating the same, a movable locking mechanism forsaid manually operated device normally out of operative position, andhaving a plug engaging part, and a removable plug for engaging said partto move said locking mechanism into operative relation with saidmanually operated device.

9. In an electro-mechanical selector, the combination with a manuallyoperated device for actuating the same, of means for returning it tonormal position, of a locking device normally out of operative position,and provided with a part for engaging the manually operated device andholding it from movement, and a removable plug for engaging said lockingdevice and forcing it into operative position.

10. In an electro-mechanical selector, the combination with'a manuallyoperated device for actuating the same, of means for returning it tonormal position, of a locking device normally out of operative position'and comprising two pivoted arms and a yielding connection between saidarms, one of said arms being movable into the path of a part connectedwith said manually operated device to lock it against movement, and aremovable plug adapted to engage the other of said arms to move thelocking de vice into operative position.

11. In an electro-mcchanical selector, the combination with a manuallyoperated device for actuating the same, and means for returning it tonormal position, of a locking device normally out of operativeposittion, provided with a part for engaging said manually operateddevice and a plug engaging part for operating the locking device, a plugsocket adjacent to said plug engaging part, a circuit through themechanism, two normally engaged contacts in said circuit, locatedadjacent to said plug socket, one of said contacts having a plugengaging part, and a removable plug for engaging said last namedcontact, for breaking said circuit, and having a part for engaging andoperating the locking device when the plug is inserted in said socket.

12. In an electro-mechanical selector, the combination with impulsetransmitting mechanism, of a step-by-step selecting device including aselecting wheel having ratchet teeth, one of which is of different depthfrom the others, a pawl engaging said teeth, and an electric device foroperating said pawl, a hit-and-miss contact device for closing a callcircuit, constructed to be thrown into operation when said pawl engagesthe distinctive ratchet tooth.

13. In an electro-mechanical selector, the combination with impulsetransmitting mechanism, of a step-by-step selecting device, including aselecting ratchet wheel, provided with a device for closing a callcircuit, a movable armature lever, and a pawl carried thereby andengaging said ratchet wheel, a flying contact in the call circuit, acontact device in said bell circuit carried by said armature lever forengaging the flying contact, and a check device for arresting the flyingcontact, said check device normally holding the flying contact out ofelectrical contact with the contact device on the armature lever.

14. In an electro-mechanical selector, the combination with impulsetransmitting mechanism, of a step-by-step selecting device, including aselecting wheel, a pawl for operating the same, and an electric devicefor actuating said pawl, a call circuit, a contact in said circuitadapted to be actuated by said pawl. to close the circuit, and a partcarried by said selecting wheel for moving said pawl into position toengage the said contact.

15. In an electro-mechanical selector, the

combination With impulse transmitting mechanism, of a step-by-stepselecting device, including a selecting wheel, a pawl for operating thesame, and an electric device for actuating said pawl, a call circuit, acontact in said circuit adapted to be actuated by said pawl to close thecircuit, said selecting wheel having ratchet teeth engaged by saidpawl,one of saidteeth being oi less depth than the others, andconstructed to move said pawl into engagementwith said contact.

16. In an electro-niechanical selector, the combination with an impulsetransmitter, step-by-step selecting device, a call circuit called intooperation by said selecting device, a telephone circuit, a switch,operated by the telephone receiver support for cutting the call circuitout of the line and cutting the telephone circuit into the line, alocking device for the impulse transmitting mechanism, a part carried bythe selecting mechanism for engaging the said locking device whenthejselecting mechanism is in normal v position and holding it out ofoperative position, a pair of normally separated contacts, in thetelephone circuit, one of said contacts being fixed and the other beingmovable and connected to said locking device, a movable part operativelyconnected with the telephone receiver support and a stop carried therebyand located normally in the path of said movable contact for holding itout of engagement with the fixed contact until the telephone receiveris'removed

